Not applicable.
1. Backgroundxe2x80x94Field of Invention
This invention relates to treatment of a lesion, specifically cancer, through the introduction of a high concentration of medication to a specific area. It will also have wide applicability in the treatment of infectious processes such as leprosy, tuberculosis, AIDS and other viral, fungal and bacterial diseases.
2. Backgroundxe2x80x94Description of Prior Art
Traditional intravenous methods of treatment are not designed to allow a high concentration of medication (chemotherapeutic agent) to be directed to a specific area without allowing the majority of the agent to escape into the bloodstream. Present chemotherapy methods entail introducing the medication into the venous flow, whereby the medical agent passes through the affected cancerous area and continues through the bloodstream to be distributed to the entire body. Consequently, the same concentration of medication that affects the cancerous area also affects the remainder of the body. As a result, healthy cells of the organism are affected to the same degree as the cancerous cells. The process does not allow complete eradication of the tumor and forces the treatments to be halted without achieving the full desired potency of the medical agent on the cancerous cells. Vital parts of the organism could be destroyed along with the cancer if the treatments are continued.
Several attempts have been made to circumvent the problems associated with existing methods of cancer treatment. Goals associated with these endeavors include increasing the concentration of medication in the target area and minimizing the concentration on the periphery. Attempts have been made to introduce the chemotheraputic agent through an injection using an indwelling catheter inserted percutaneously and directed to the tumor. An external tourniquet is applied for five minutes on the treated extremity. This action temporarily stops, or decreases, the arterial blood flow and confines the chemotherapeutic agent to the regional tissue, while simultaneously blocking the venous return. (C. Karakousis, Cancer Drug Delivery, 1985).
The logic of our critique follows that after the tourniquet is removed, the regular blood flow begins to disseminate the medication throughout the body. Five minutes of exposure is insufficient for the medication to exert a marked effect on the tumor.
Other attempts introduced the medication intra-arterially to the corresponding area of the lesion. (Greenberg, H. S., et al, Journal of Neurosurgery, 1984). Following this process, however, the medication would escape into the main blood stream after the first pass, producing the exact same effects as those plaguing the present methods.
Further improvement of the above method, introducing the medication intra-arterially, involves isolated perfusion with the simultaneous collection of venous blood from the same area. This process re-circulates, or detoxifies, the venous blood. Constant and lengthy perfusion of a specific, given area, is now permitted, preventing dissemination of the medication to the rest of the body by shunting blood through the lesion via the arterio-venous axis as discussed in U.S. Pat. No. 4,192,302 (1980). (Stehlin, J. S., Arch Surg, 1962). Unfortunately these methods bypass interstitial space where the lesion resides.
Another method, created by Reynaldo Calderon in U.S. Pat. No. 4,867,742 (1989) and U.S. Pat. No. 4,714,460 (1987), places focus on the introduction of the medication intravenously in the retrograde fashion. However, problems arise from the necessity to reverse the blood flow in the vein in order to bring the medication upstream. Immense pressure is required to assure delivery of the medical agent to the capillary level.
The capillary, which functions at a pressure of approximately 7 mm of mercury, is now forced to endure a pressure between 120 and 150 mm of mercury, the usual systolic blood pressure. As a result the tissue will be destroyed before the medication is delivered. For these reasons this method is unsuccessful.
All of the above-described methods disregard the anatomical and physiological relationships inside the body, utilizing a one-dimensional mode of circulation: arterial-to-venous. In truth, though, blood is delivered to the periphery by the arterial system. The outflow is assured by two separate systems, venous and lymphatic (FIG. 1). In order to reach the lesion, it is necessary to traverse interstitial space, the area where the cells of the organs are located and in which the lesion (cancer) resides. A cure is only possible when direct contact between the medication and the cancer is maintained for a prolonged period of time, while sparing the rest of the body.
Medication introduced by the previously-described methods bypasses the interstitial space, keeping medication inside the arterio-venous axis, preventing it from penetrating into the interstitial space. Allowing the maximum quantity of medication into the interstitial space is the only method to keep a therapeutic concentration of the drug in contact with the lesion. The neoplastic growth (cancer) resides within the interstitial area as do bacteria, fungi, and viruses. All our efforts should be focused on this region (FIG. 2).